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Winter storm produces heavy snowfall (with some lightning) across parts of the Northeast US

GOES-16 Mid-level Water Vapor (6.9 µm) images with an overlay of GLM Flash Extent Density (above) showed that there were isolated brief periods of lightning activity over parts of West Virginia / Maryland / Pennsylvania during the nighttime hours, followed by more activity off the south coast of Massachusetts during... Read More

GOES-16 Mid-level Water Vapor (6.9 µm) images with an overlay of GLM Flash Extent Density, with/without plots of 15-minute METAR surface reports, from 0601-1906 UTC on 13 February [click to play animated GIF | MP4]

GOES-16 Mid-level Water Vapor (6.9 µm) images with an overlay of GLM Flash Extent Density (above) showed that there were isolated brief periods of lightning activity over parts of West Virginia / Maryland / Pennsylvania during the nighttime hours, followed by more activity off the south coast of Massachusetts during the daytime hours on 13 February 2024. Although this lightning was occurring near areas receiving moderate to heavy snowfall, there were no METAR sites that explicitly reported thundersnow.

As clouds slowly began to clear, GOES-16 Day Cloud Type RGB images (below) began to reveal areas with appreciable snow cover (darker shades of green).

GOES-16 Day Cloud Type RGB images, from 1501-2101 UTC on 13 February [click to play animated GIF | MP4]

On the following day, with minimal cloud cover RGB imagery showed the areal extent of the swath of fresh snow cover that extended from West Virginia to Massachusetts (below). Notable snowfall accumulations included 15+ inches in Pennsylvania, New Jersey and Connecticut (storm summary).

GOES-16 Day Cloud Type RGB images, from 1501-2101 UTC on 14 February [click to play animated GIF | MP4]

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VIIRS imagery of a low pressure system near the North Pole

A sequence of Suomi-NPP VIIRS Infrared Window (11.45 µm) images (above) displayed the development of a coma-shaped cloud structure associated with a low pressure system near the North Pole (northwest of Greenland) on 13 February 2024. The single METAR surface report plotted is Svalbard, Norway (the reports for CWLT —... Read More

Suomi-NPP VIIRS Infrared Window (11.45 µm) images, from 2100 UTC on 12 February to 2213 UTC on 13 February [click to play animated GIF | MP4]

A sequence of Suomi-NPP VIIRS Infrared Window (11.45 µm) images (above) displayed the development of a coma-shaped cloud structure associated with a low pressure system near the North Pole (northwest of Greenland) on 13 February 2024. The single METAR surface report plotted is Svalbard, Norway (the reports for CWLT — Alert, Nunavut, Canada — were not available).

Analyses from the Canadian Meteorological Centre (below) showed the evolution of the surface low.

Surface analyses from 0600 UTC on 13 February to 0000 UTC on 14 February [click to play animated GIF]

Given the relatively frequent overpasses of polar-orbiting satellites over the high latitudes, cloud-tracked Atmospheric Motion Vectors (AMVs) can be calculated using Infrared data from VIIRS — examples that combine AMVs from Suomi-NPP and NOAA-20 (source) are shown below.

Infrared images from Suomi-NPP and NOAA-20, with overlays of Atmospheric Wind Vectors, from 1311-2138 UTC on 13 February

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MIRS Rain Rate from Direct Broadcast

CSPP software processes signals at Direct Broadcast antenna sites to create products and imagery with very low latency from Low-Earth Orbit (LEO) satellites. The software includes Microwave Integrated Retrieval System (MIRS) algorithms, including rain rate (available here). How well does that product do in capturing observed precipitation? The toggle above shows... Read More

GOES-16 Band 13 (Clean Window, 10.3) infrared imagery with ATMS Rain Rate overlain, 1750 UTC on 13 February 2023 (Click to enlarge)

CSPP software processes signals at Direct Broadcast antenna sites to create products and imagery with very low latency from Low-Earth Orbit (LEO) satellites. The software includes Microwave Integrated Retrieval System (MIRS) algorithms, including rain rate (available here). How well does that product do in capturing observed precipitation? The toggle above shows GOES-16 Clean Window infrared imagery and derived rain rates (derived from microwave data). The back edge of the precipitation is captured well by the MIRS product, and several heavier bands of precipitation offshore are also suggested. This product is especially useful in the absence of any radar.

How does the rain rate compare to the radar at the same time? The image below (from the College of DuPage website) shows Mosaic Reflectivity at 1750 UTC on 13 February. The back edge of the precipitation in the radar shows agreement with the Rain Rate shown in the toggle above (or here).

Composite Reflectivity from the COD website, 1750 UTC on 13 February 2024 (click to enlarge)

The side-by-side comparison, below, highlights detected features. The precipitation band circled in purple appears in both Rain Rate and Radar imagery. The heavier precipitation regions to the east, highlighted by the blue arrows, does not appear in the radar, and highlights an advantage of MIRS Rain Rate: it provides information where radar data are not available.

MIRS Rain Rate (left) and NEXRAD Radar Mosaic, 1750 UTC on 13 february 2024 (Click to enlarge)

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Wind, Storms, and Gales in Alaska

On February 12, 2024, much of inland Alaska is experiencing warnings for wintery precipitation, while coastal Alaska is under warnings for storms, gales, and heavy freezing spray. Southeastern Alaska is also under a small craft advisory.The low-pressure system associated with this inclement weather is seen easily from the GOES-West imagery.... Read More

On February 12, 2024, much of inland Alaska is experiencing warnings for wintery precipitation, while coastal Alaska is under warnings for storms, gales, and heavy freezing spray. Southeastern Alaska is also under a small craft advisory.

Figure 1: Hazards issued by the National Weather Service for Alaska on 2024-02-12.

The low-pressure system associated with this inclement weather is seen easily from the GOES-West imagery. Viewers can see a large hook-shaped rotational system swooping in from the south and affecting much of the state. Figure 2 shows Band 9, the mid-level water vapor channel, from GOES-West, illustrating the low pressure system nicely. On the GOES-West Advanced Baseline Imager (ABI), Band 9 is centered on 6.9 µm and is great for tracking storm systems.

Figure 2: An animation of GOES-West Band 9 imagery from 2024-02-12 at 1430Z to 2024-02-12 at 2030Z. Viewers can recreate this animation using RealEarth.

Expectedly, the weather is having unfavorable effects on aviation safety. Marginal visual flight rules (MVFR) cite weather conditions that aircraft pilots can experience at land or ocean surface levels. As seen in Figure 3, satellite and model-derived MVFR probabilities are present throughout inland and coastal areas of Alaska.

Figure 3: An animation of GOES-West MVFR probability from 2024-02-12 at 1430Z to 2024-02-12 at 2030Z. Viewers can recreate this animation using RealEarth.

The animations in this post are replicable for anyone with web access, using RealEarth. RealEarth is a free weather visualization application. To recreate the animations you see in this post, click the links in the animation captions.

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